Combustor and method for supplying fuel to a combustor

Abstract

A combustor includes an end cover, an end cap downstream from the end cover, and tubes that extend through the end cap. An outer support tube extends downstream from the end cover and connects to an upstream surface of the end cap. An inner support tube extends downstream from the end cover and connects to a downstream surface of the end cap. A first plenum surrounds the inner support tube between the end cover and the upstream surface and extends radially between the upstream and downstream surfaces. A second plenum surrounds the first plenum between the end cover and the upstream surface and extends radially between the upstream and downstream surfaces.

What is claimed is: 
     
         1 . A combustor, comprising:
 a. an end cover;   b. an end cap downstream from the end cover that extends radially across at least a portion of the combustor, wherein the end cap comprises an upstream surface axially separated from a downstream surface;   c. a plurality of tubes that extends from the upstream surface through the downstream surface to provide fluid communication through the end cap;   d. an outer support tube that extends downstream from the end cover and connects to the upstream surface of the end cap;   e. an inner support tube that extends downstream from the end cover and connects to the downstream surface of the end cap;   f. a first plenum that surrounds the inner support tube between the end cover and the upstream surface, wherein the first plenum extends radially between the upstream and downstream surfaces; and   g. a second plenum that surrounds the first plenum between the end cover and the upstream surface, wherein the second plenum extends radially between the upstream and downstream surfaces.   
     
     
         2 . The combustor as in  claim 1 , wherein the first plenum extends radially inside the end cap downstream from the second plenum. 
     
     
         3 . The combustor as in  claim 1 , wherein the first plenum is in fluid communication with a first set of the plurality of tubes and the second plenum is in fluid communication with a second set of the plurality of tubes. 
     
     
         4 . The combustor as in  claim 1 , further comprising a barrier that extends between the first and second plenums, wherein the barrier extends axially between the first and second plenums upstream from the upstream surface. 
     
     
         5 . The combustor as in  claim 4 , wherein the barrier extends radially between the first and second plenums downstream from the upstream surface. 
     
     
         6 . The combustor as in  claim 1 , further comprising a fuel plenum inside the inner support tube. 
     
     
         7 . The combustor as in  claim 1 , further comprising a casing that circumferentially surrounds at least a portion of the end cap to define an annular passage between the end cap and the casing and a support extends radially between the end cap and the casing in the annular passage. 
     
     
         8 . The combustor as in  claim 1 , further comprising a cap shield that circumferentially surrounds the end cap. 
     
     
         9 . The combustor as in  claim 8 , further comprising a sliding engagement between the end cap and the cap shield. 
     
     
         10 . A combustor, comprising:
 a. an end cover;   b. a fuel conduit that extends downstream from the end cover;   c. a downstream surface connected to the fuel conduit, wherein the downstream surface extends radially across at least a portion of the combustor;   d. an upstream surface axially separated from the downstream surface, wherein the upstream surface extends radially across at least a portion of the combustor;   e. a plurality of tubes that extends from the upstream surface through the downstream surface to provide fluid communication through the upstream and downstream surfaces;   f. a first plenum that surrounds the fuel conduit between the end cover and the upstream surface, wherein the first plenum extends radially between the upstream and downstream surfaces; and   g. a second plenum that surrounds the first plenum between the end cover and the upstream surface, wherein the second plenum extends radially between the upstream and downstream surfaces.   
     
     
         11 . The combustor as in  claim 10 , wherein the first plenum extends radially between the upstream and downstream surfaces downstream from the second plenum. 
     
     
         12 . The combustor as in  claim 10 , wherein the first plenum is in fluid communication with a first set of the plurality of tubes and the second plenum is in fluid communication with a second set of the plurality of tubes. 
     
     
         13 . The combustor as in  claim 10 , further comprising a barrier that extends between the first and second plenums. 
     
     
         14 . The combustor as in  claim 10 , further comprising an outer support tube that extends downstream from the end cover and connects to the upstream surface. 
     
     
         15 . The combustor as in  claim 10 , further comprising a flexible coupling between the end cover and the fuel conduit. 
     
     
         16 . The combustor as in  claim 10 , further comprising a barrier that extends between the first and second plenums, wherein the barrier extends axially between the first and second plenums upstream from the upstream surface. 
     
     
         17 . The combustor as in  claim 16 , wherein the barrier extends radially between the first and second plenums downstream from the upstream surface. 
     
     
         18 . A method for supplying fuel to a combustor, comprising:
 a. flowing a working fluid through a plurality of tubes radially arranged in an end cap, wherein the end cap extends radially across at least a portion of the combustor;   b. flowing at least one of a first fuel or a first diluent through a first plenum, wherein the first plenum is at least partially defined by an inner support tube that connects to a downstream surface of the end cap; and   c. flowing at least one of a second fuel or a second diluent through a second plenum that circumferentially surrounds at least a portion of the first plenum, wherein the second plenum is at least partially defined by an outer support tube that connects to an upstream surface of the end cap.   
     
     
         19 . The method as in  claim 18 , further comprising flowing a third fuel inside the inner support tube. 
     
     
         20 . The method as in  claim 18 , further comprising flowing at least one of the first fuel or first diluent radially inside the end cap downstream from the second plenum.